This invention relates generally to electrical connectors and, more particularly, to electrical connectors configured to carry high voltages while providing limited mechanical resistance to coupling and uncoupling.
Examples of electrical connectors of this particular kind are disclosed in U.S. Pat. No. 4,605,272 issued to Myers et al. One of the connectors disclosed in the patent includes mating connector halves in the form of a plug assembly and a receptacle assembly, each carrying an electrical contact configured to mate with the other. The plug assembly includes a dielectric sleeve having a cylindrical nose and carrying a female contact, or contact socket, coaxially within the nose. The receptacle assembly includes a dielectric receptacle insulator having a cylindrical cavity and carrying a male contact, or contact pin, coaxially within the cavity. The receptacle assembly further includes a resilient sleeve, or seal, located within the cavity, concentric with the cavity""s cylindrical side wall.
In use, the plug assembly is mated with the receptacle assembly by mechanically inserting the nose of the plug assembly into the resilient seal located within the cavity of the dielectric receptacle insulator. This couples together the contacts of the two assemblies. The resilient seal is specially configured such that, when the two assemblies are mated, the seal substantially fills the annular space between the concentric side walls of the plug assembly""s nose and the side wall of the receptacle assembly""s cavity. In this mated condition, a series of aligned circumferential ribs in the seal""s inner and outer surfaces are compressed radially, to provide a reliable dielectric seal. By substantially filling the annular space between the two concentric side walls, the risk of undesired corona discharge is minimized.
One important feature of the electrical connector of the Myers et al. patent is that only the annular ribs of the resilient seal are radially compressed between the concentric side walls when the plug and receptacle assemblies are coupled together. Consequently, the seal provides only limited mechanical resistance to coupling and uncoupling of the two assemblies. Nevertheless, this limited mechanical resistance is considered excessive, especially in the case of connectors having multiple contacts. The need to overcome this mechanical resistance can require unduly high insertion forces and, in some cases, can even damage the resilient seal.
It should, therefore, be appreciated that there is a need for an improved electrical connector configured to reliably couple high-voltage electrical signals while offering even lower mechanical resistance to coupling and uncoupling. The present invention fulfills this need and provides further related advantages.
The present invention is embodied in an improved electrical connector having mating plug and receptacle assemblies configured to reliably couple high-voltage electrical signals while offering only insubstantial mechanical resistance to coupling and uncoupling. The plug assembly includes: (1) a plug insulator having a nose, (2) an electrical contact supported within the nose of the plug insulator, and (3) a seal compressor. The receptacle assembly includes: (1) a receptacle insulator having a cavity defined by a side wall, and (2) an electrical contact supported within the cavity. Both the plug insulator and the receptacle insulator are formed of a substantially non-resilient dielectric material. When the plug assembly and receptacle assembly are engaged with each other, the nose is positioned within the cavity and the contacts are electrically coupled to each other, at which time an annular space is define between the nose and the cavity wall. The connector further includes a resilient dielectric seal fitted either onto the nose of the plug assembly or within the cavity of the receptacle assembly, such that the seal is interposed in the annular space define between the nose and the cavity wall when the plug assembly and receptacle assembly are engaged with each other. The seal has a prescribed nominal radial thickness profile sized such that the plug assembly and receptacle assembly can be couple to each other without substantial sliding resistance. The seal compressor of the plug assembly is operable when the plug assembly and receptacle assembly are coupled together, to increase the nominal radial thickness profile of the resilient dielectric seal until the seal substantially fills the annular space between the nose and the cavity wall.
In more detailed features of the invention, the resilient dielectric seal and the seal compressor both are substantially cylindrical. The seal compressor is part of a plug body, and it is configured to encircle a portion of the nose and to engage one end of the resilient dielectric seal. Further, the plug assembly and receptacle assembly, together, further include a rotatable coupling nut and mating threads, for tightening the engagement between the two assemblies and simultaneously moving the cylindrical seal compressor relative to the nose, to compress the resilient dielectric seal longitudinally. Rotation of the coupling nut relative to the mating threads advances the cylindrical seal compressor toward the receptacle assembly, while the plug insulator and nose retract relative to it. Means also are included, e.g., a compression spring, for yieldably resisting retraction of the nose relative to the cylindrical seal compressor.
In other more detailed features of the invention, the resilient dielectric seal has nominal radial thickness profile that is substantially uniform around its entire circumference. The seal also can include a plurality of circumferential ribs, to enhance the dielectric seal it provides. Preferably, the seal is formed of silicone rubber.